Process for cracking oil



April 19, 1932. c. P. DUBBS PROCESS FOR CRACKING OIL original Filed oct. e, 1920 Patented Apr. 19, 1932 UNITED STATES Param OFFICE CARBON IDUBBS,l OF WILMETTE, ILLINOS, ASSTGNOR TO UNVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLTNOIS, A` CORPORATION OF vSOUTIEI DAKOTA rnoonss rcncanciiive OIL i Application filed October 6, 1920, Serial No. 415,137, Renewed March 10, 1927.

This invention relates to a process for cracking oil and refers more particularly to the cracking of relatively heavy petroleums or petroleum distillates into light hydrocarbons such as gasoline, kerosene or the like.

The present invention consists in providing a process in which the oil is treated at successively decreasing pressures Which drops in pressure are always at the same rate, relative to each other and are all controlled from the outlet side of the receiver or final condenser. This is accomplished by inserting automatic pressure valves in the desired parts of the system.

The following illustration Will clearly show the essence of the invention: Assume the still is initially subjected to 300 lbs. pressure, then the automatic valves may be so adj usted that the pressure on the dephlegmator is say, 290 pounds and on the receiver and Water condenser 280 pounds. By suitably regulating the outlet valves from the receiver, pressure on the still may be reduced to 290 pounds, which will automatically reduce the pressure on the dephlegmator to 280 pounds and on the Water condenser to 270 pounds. This arrangement may permit of subjecting the vapors to condensing action in more eX- panded or attenuated form than Where they are condensed under the same pressure as the still pressure. Y

Figure 1 is a diagrammatic illustration in side elevation of the apparatus employed in carrying out the process shown partly in section.

Fig. 2 is a sectional vievv of the pressure valve employed.

In the particular embodiment of myinvention shown in the drawings, 1 designates the furnace having burner 2, bridge Wall 3 and stack 4. In this furnace is mounted the still 5, which in the present instance is shown on Ithe cylindrical or shell type. This still is provided With residue drawoif 6, controlled by throttle valve 7 and with charging line 8 connected With feed pump 9, this pump 9 being provided With suitable valves 10 and 11 on its inlet and discharge sides respectively. Vapors pass out of the still 5 through the gooseneck or vapor outlet 12, which vapor outlet extends as shown at 13 into the lovver end of a dephlegmator 14. A spaced cap memberl is mounted above the pipe 13, the arrangement being such as to permit the oil orvaporsto pass into the dephlegmator While preventing lthe refiux'condensate from falling back into the pipe 12. Instead, the refiuX condensate is dravvn off from the bot-` tom ofthe dephlegmator through pipe 16 leading to the charging line Sand provided with throttle valve 17.

Tf desired, the reflux condensatemay vbe dravvnV off throughithe branch line18-controlled by throttle valve 19 to any other re ceptacle or still. The upper "end of vthe dephlegmator is provided With av vapor outlet pipe 20, which leads to Water condenser coil 21 seated in condenser boX 22. This condenser coil 21 in turn connects tothe upper end of receiver 23. This receiver 23 is provided With liquid level gauge 24:, pressure gauge 25, liquid dravvoff 26 and gas outlet pipe 27. The pipes 26and 27 areV provided ivith throttle ,valves 28'a'n`d 29 respectively.l vThe still 5A is provided with pressure .gauge 30 andthe dephlegmator Withv a pressure gauge 80a.

As a feature of my invention, I insert in the vapor line 12 an automatic regulating pressure valve 31 andl I also insert in the line20 a similar automatic regulating valve Y sion of a compensating spring as shown in n Fig. 2, which spring acts 1n conjunction With the lower pressure to maintain the balanced condition. The pressure of 290 pounds on the dephlegmator will be balanced by a pressure of 280 pounds on the receiver. It will I be apparent that by reducing the pressure on the receiver Vfrom 280A pounds to `270 pounds, there will be a corresponding drop of 10 lbs. on both the still'and dephlegmator.V

1 dephlegmator and still.

' sure may be reduced ten pounds on each part s water condenser;

pressure will only Vbe between the still and The process maybe operated as follows: The still may be charged with a mid-continent gas oil or fuel oilrand subjected to a pressure of 300 pounds in the still for a period of say, three hours. At this time, theV pressure on the dephlegmator may be 290 pounds and onA the receiver 280 pounds, depending on the manner in which the automatic valves are adjusted. For the next hour, the presofgthey systemand a further reduction of ten pounds for every hour until the entire pressure lhas been reduced to say, pounds. Duringall this time, the -oil in the still In? berlreated to a temperature ofsa-y, 750 degs.

Asa modified method of carryingou-t the process, they still temperature may be continuously reduced as the still pressure is reduced; The reflux condensatey may be returned in Veither case .continuously to the system or drawn oil' elsewhere.

a further modification of the process, the automatic: valve 32 between. the dephl'egmator and condenser may be cut out of the systemfaltogether and the vapors allowed to pass freely from the dephlegmator to the In' such case,` the different the remainder 'of the system.

As ar still furthermodifi'cation of the process, the automatic valve 3l may bev cut out ofthe: system and the vapors allowed to pass freely'from the still 5- to the dephlegmator. Infl this case, there will beY a different pres,- surez-.onily betweenv the stil-l and dephlegmator on the one hand and the water condenser'and receiver on theother.Y

I claima-s invention.:

-L Alcontinuous process for cracking eil,

consisting in subjecting the oil in a heating'v zone to cracking conditions of temperatureandpressu-re,in passing the-generafte-dzvapors toa dephlegm-ator, in passing the clephleg- Vfimated vapors from the deplrlegmator toa condenser and in collecting-the resulting dis'- tillate, in maintaining an initial predeter- Inmedpressure on the oil in the heating zone and apredetermined lower pressure on the :oil the deplilegniator, in maintaining' in thecondenser--a'predeterminedlower pressure tha-n maintainedinl-the dephleginator', and in gradually reducing the pressure throughout the.v system as the treatment of the oil prolceedswhi-le maintaining constant the prede-- temrined differencein pressure between the heating zone and the dephlegmator and between the dephlegmator vandthe condenser;

.2. A process of cracking oil,l consisting'in Hi''continuously passing-oil to a heating zone llower pressure in the condenser than in the dephlegmator, in gradually reducing the pressure on the system while maintaining consta-nt the difference in' pressure between the heating Vzone and they dephlegrnat'or and between the dephlegmator and the condenser.

CARBON P. DUBBS.

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